|
Great article. Thanks for posting Rick and thanks to Richard for the detailed write up.
The airy disc rings showing up on some brighter stars is kind of what I thought was going on. So when you have a higher QE cameras those outer rings of the airy disc can show up giving wider stars. The detection limit concept of wider stars when they are fully bright to expose the whole airy disc and get it above the read noise is quite a visible phenomenom when processing images from some cameras.
Also there is another question mark over how well antiblooming works on all chips.
So from this we get what? - with high QE small well low read noise sensors it makes more sense to do shorter subs and keep the airy disc outer rings below the detection limit to get tighter stars. Use longer exposures with sensors with deeper wells and higher read noise.
Also fast scopes get tighter stars. An interesting one. ASA Newts always seemed to me to have the smallest stars. Newts in general seem to have tighter stars than other systems. I guess they are often fast compared to other scopes.
Greg.
|